This package exports three classes to generate lazily combinations,
and arrangements with and without repeatition (permutations).
See also: <http://fr.wikipedia.org/wiki/Combinatoire>
License:
AGPL3
Copyright Pascal J. Bourguignon 2003 - 2012
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program.
If not, see <http://www.gnu.org/licenses/>

README:

FUNCTION

Public

ARRANGEMENT (K N)

RETURN: The number of arrangement of k elements (without repeat) taken amongst n.

COMBINATIONS (LIST N)

Private

Undocumented

NEXT-STEP (CHOICE LIMIT I)

TEST

GENERIC-FUNCTION

Public

DONE-P (SELF)

RETURN: !atBegining()
&& ((cardinal()=0) || (index()=cardinal())).

GET-CURRENT-ELEMENT (SELF)

PRE: cardinal()>0.
POST: !atBegining(),
RETURN: A vector of cardinal: choice.
DO: Sets the choice array to the current enumerated
element. (ie. the last element retrived with the
getNextElement method). The choice array must contain
at least elementSize() integers.

GET-NEXT-ELEMENT (SELF)

PRE: cardinal()>0, !done-p(), atBegining()=b,
(!b => index()=a).
POST: !atBegining(), (!b => index()=a+1),
RETURN: A vector of cardinal: choice; done-p.
DO: Computes the next element to be enumerated and sets the
choice array to it. It returns TRUE when the last
element is retrived, ie. all elements have been
enumerated. The choice array must contain at least
elementSize() integers.

RESET (SELF)

POST: atBegining().
DO: resets the enumeration.

Private

COMPUTE-CARDINAL (SELF)

NOTE: It must be overriden by subclasses to compute the
_cardinal from the _baseCardinal and the _elementSize
attributes.

INITIALIZE (SELF)

NOTE: It must be overriden by subclasses to initialize the
enumeration. It must compute the _cardinal, and set
the_index either to 0 or to _cardinal. If
_index != _cardinal then the choice array must be
set to the first enumerated element.

NEXT (SELF)

NOTE: It must be overriden by subclasses to step to the next
element of the enumeration. If _index<_cardinal, then
it must increment _index ; if _index¹_cardinal then the
choice array must be set to the first enumerated
element.

Undocumented

SET-BASE-CARDINAL (FUNCTOR CARDINAL)

SET-ELEMENT-SIZE (FUNCTOR SIZE)

STEP (FUNCTOR INDEX)

SLOT-ACCESSOR

Public

AT-BEGINNING-P (SELF)

The
RETURN: whether the reset() method has been called and
getNextElement() (or getCurrentElement()) has not
already been called.

BASE-CARDINAL (FUNCTOR)

The RETURN: The cardinal n of the base set.

CARDINAL (SELF)

The
PRE: !atBegining()..
RETURN: the number of elements enumerated by this object.

ELEMENT-SIZE (SELF)

The
RETURN: the size of each element returned by getCurrentElement
and getNextElement in the choice arrays.

INDEX (SELF)

The
PRE: !atBegining()..
RETURN: the index of the current element enumerated by
this object.

CLASS

Public

ARRANGEMENT-SANS-REPEAT

We choose k objects in order without repeating the same object, amongst n objects.

ARRANGEMENT-WITH-REPEAT

We choose k objects in order possibly repeating the same object, amongst n objects.